Power control unit

1. A power control apparatus for controlling charging and discharging of a plurality of storage means, said power control apparatus comprising: voltage measuring means for measuring voltages of each of said storage means: current measuring means for measuring currents flowing through each of said storage means; a status detecting means for detecting an operating status of each storage means, from values measured by said voltage measuring and current measuring means; and a charging/discharging controlling means for controlling currents, voltages, or power according to the operating status of each storage means detected by said status detecting means, to charge or discharge said storage means; wherein: said status detecting means calculates an internal impedance or open circuit voltage of each storage means; and said charging/discharging controlling means calculates a permissible charging or discharging current value of each storage means from its internal impedance, open circuit voltage, preset maximum permissible voltage and minimum permissible voltage, calculates a sum of all currents flowing through said storage means to suppress a current over the calculated permissible charging or discharging current from flowing into or out of each of said storage means, and controls the charging or discharging current to maintain the total current below the calculated total current value.

2. The power control apparatus of claim 1 , wherein said storage means comprises a device selected from the group consisting of a lithium secondary cell, a nickel metal-hydride battery, a lead-acid battery, and an electric double layer capacitor.

3. The power control apparatus of claim 1 , wherein said storage means supplies power to an electric motor which drives vehicle wheels, and is charged by power generated by a dynamo-electric generator that is driven by an internal combustion engine on a vehicle or power from said electric motor when said motor is used as a power generator.

4. The power control apparatus of claim 1 , wherein said status detecting means calculates the charging status of each storage means and determines a maximum or minimum of the calculated charging states; and said charging/discharging controlling means controls the charging current, voltage, or power by the maximum charging status value and controls the discharging current, voltage, or power by the minimum charging status value.

5. The power control apparatus of claim 1 , wherein: said power control apparatus further comprises a switch which selectively breaks or makes a connection between said charging/discharging controlling means and any storage means; and said charging/discharging controlling means checks the on/off status of said switch and controls the current, voltage or power according to the detected on/off status of said switch and the running status of each storage means to discharge or charge the storage means.

6. The power control apparatus of claim 5 , wherein: said status detecting means calculates the internal impedance or open circuit voltage of each storage means; and said charging/discharging controlling means controls charging/discharging currents, voltages, or power of said storage means according to the impedances or open circuit voltages thereof.

7. The power control apparatus of claim 5 , wherein: said status detecting means calculates the charging status of each storage means and determines the maximum or minimum of the calculated charging states; and said charging/discharging controlling means controls the charging current, voltage, or power by the maximum charging status value and controls the discharging current, voltage, or power by the minimum charging status value.

8. The power control apparatus of claim 1 , further comprising: a load; and a power source selected from the group consisting of a commercial power supply, a solar energy generator, a micro gas turbine generator and a fuel cell, to supply power to said loads; wherein said power control apparatus supplies power to said load or said commercial power supply and uses power from said power source.

9. The power control apparatus of claim 1 , wherein said storage means supplies power to an electric motor which drives vehicle wheels, and is charged by power from outside of a vehicle or power from said electric motor when said motor is used as a power generator.

10. A power control apparatus for controlling charging of a plurality of storage means, said power control apparatus comprising: voltage measuring means for measuring voltages of each of said storage means; current measuring means for measuring currents flowing through each of said storage means; a status detecting means for respectively calculating internal impedances and open circuit voltages of each of said storage means, from values measured by said voltage and current measuring means; and a charging current controlling means which calculates a permissible charging current value of each storage means from its internal impedance or open circuit voltage and a preset maximum permissible charging voltage which are detected by said status detecting means, calculates a sum of all currents flowing through said storage means to suppress a current over the calculated current from flowing into said storage means, and controls the charging current to maintain the total current below the calculated total current value.

11. The power control apparatus of claim 10 , wherein said storage means comprises a device selected from the group consisting of a lithium secondary cell, a nickel metal-hydride battery, a lead-acid battery, and an electric double layer capacitor.

12. A power control apparatus for controlling discharging of a plurality of storage means, said power control apparatus comprising: voltage measuring means for measuring voltages of each of said storage means; current measuring means for measuring currents flowing through each of said storage means; a status detecting means for calculating internal impedances and open circuit voltages of said storage means, from values measured by said voltage and current measuring means; and a discharging current controlling means which calculates a permissible discharging current value of each storage means, from its internal impedance or open circuit voltage and a preset maximum permissible discharging voltage which are detected by said status detecting means, calculates a sum of all currents flowing through said storage means to suppress a current over the calculated current from flowing from said storage means, and controls the discharging current to maintain the total current below the calculated total discharging current value.

13. The power control apparatus of claim 12 , wherein said storage means comprises a device selected from the group consisting of a lithium secondary cell, a nickel metal-hydride battery, a lead-acid battery, and an electric double layer capacitor.